1. Field of Invention
The invention relates to a light emitting apparatus and in particular, to a light emitting apparatus having good heat dissipating efficiency.
2. Related Art
With the development of the optoelectronic industry, light emitting devices, such as LEDs (Light Emitting Diodes), have been widely and variously applied to display functions of electronic products.
Referring to FIG. 1, a conventional LED light emitting apparatus 1 includes a substrate 10, an insulating layer 11, a plurality of light emitting devices 12, a metal layer 13 and a package layer 14. The insulating layer 11 is disposed on the substrate 10. The light emitting devices 12, which are light emitting diodes (LEDs), are disposed on the insulating layer 11. The metal layer 13 is disposed on the insulating layer 11 and electrically connected to the light emitting devices 12 by wire bonding. The package layer 14 encapsulates the light emitting devices 12 to protect them from being influenced and damaged by mechanical factors, heat, moisture or other factors.
With the development of ever higher efficiency and ever higher luminance of the light emitting apparatus 1, the light emitting device 12 generates heat while operating, and the accumulated heat raises the temperature, influencing the light emitting efficiency and the lifetime of the light emitting device 12. However, the conventional light emitting device 12 is disposed on the insulating layer 11 with a poor heat dissipating property, and the heat generated by the light emitting device 12 can not be dissipated easily due to the airtight seal of the package layer 14. Thus, the heat dissipating problem becomes increasingly significant.
To solve the above mentioned problem, the conventional light emitting apparatus 1 usually adopts the substrate 10 that is made of ceramic, copper, copper alloy or thermal conductive material. In addition, the insulating layer 11 is connected to the substrate 10 by thermal conductive adhesive. However, the heat dissipating efficiency will be affected by the thermal resistance caused by the insufficient thermal conductivity of the adhesive. Moreover, the degrading adhesive may also shorten the lifetime of the light emitting apparatus 1.
Therefore, it is an important subject to provide a light emitting apparatus, which has enhanced heat dissipating efficiency and good product reliability.